In industrial screening it has been proposed to increase screen output by employing a relatively long screen surface and depositing material thereon at several points along the screen surface. In such proposals the oversize material from all the points of deposit carries along to the end of the screen and therefore the material to be screened which is deposited on the screen at the last point of deposit is deposited on the oversize material from the previous points of deposit. Accordingly, the efficiency of screening is not uniform throughout the length of the screen and the screening result is not uniform. Furthermore, since the material deposited on the screen at various points therealong travels various distances along the screen surface the screening action is not uniform as to the several deposits.
Another and more obvious alternative, when increased screening capacity is required, is to merely employ additional entirely separate and independent screening apparatuses of conventional form.